Orthodontic bracket with integral ball hook and method of making

Abstract

A machined orthodontic bracket has a hook integrally formed with a gingival tiewing of the bracket. The hook includes a square shank, and a head with a cylindrical surface. The hook is machined by an end mill or formed cutter, and is achieved in part by changing the orientation of the bracket midway through the machining operation.

We claim: 
     
       1. An orthodontic bracket comprising a base, a body extending from the base and a tiewing extending from the body, said bracket including a hook connected to said tiewing, said hook including an elongated shank and a head, said head having a mesiodistal width that is greater than the mesiodistal width of said shank and a labiolingual depth that is greater than the labiolingual depth of said shank, said hook and said tiewing being integrally formed during a machining operation, and wherein said shank includes fillets integrally connected to said tiewing and fillets integrally connected to said head. 
     
     
       2. The bracket of claim 1, wherein said head includes a generally cylindrical surface that extends about a reference axis generally perpendicular to an occlusal reference plane of the bracket when viewed toward its labial side. 
     
     
       3. The bracket of claim 1, wherein said shank has a rectangular cross-section in reference planes transverse to the longitudinal axis of said shank. 
     
     
       4. An orthodontic bracket comprising a base, a body extending from the base and a tiewing extending from the body, said bracket including a hook connected to said tiewing, said hook including an elongated shank and a head, said head having a mesiodistal width that is greater than the mesiodistal width of said shank and a labiolingual depth that is greater than the labiolingual depth of said shank, said hook and said tiewing being integrally formed during a machining operation, wherein said head includes an outermost gingival surface having a general shape of a partial cylinder. 
     
     
       5. A method for making an orthodontic bracket having a hook comprising the steps of: shaping stock to form surfaces generally corresponding to labial sides of an occlusal and a gingival tiewing of the bracket, as well as to form surfaces generally corresponding to labial and lingual sides of a hook of the bracket;   cutting the stock along spaced apart reference lines to form surfaces generally corresponding to mesial and distal sides of occlusal and gingival tiewings of the bracket and also to remove portions of the stock located on mesial and distal sides of the hook;   moving a cutting tool along a path generally parallel to the labial surface of the bracket in order to form surfaces generally corresponding to an occlusal edge of the occlusal tiewing, a gingival edge of the hook, and a pair of notches of the hook; and   moving a cutting tool along a path about an axis generally perpendicular to the occlusal plane of the bracket when viewed toward a labial side of the bracket to form surfaces generally corresponding to mesial, distal, labial and lingual surfaces of a head of the hook.   
     
     
       6. The method of claim 5, wherein said step of cutting the stock along spaced apart reference lines includes the step of rotating a rotary cutter. 
     
     
       7. The method of claim 5, wherein said step of moving a cutting tool along a path about an axis generally perpendicular to the occlusal plane includes the step of moving the cutting tool along a circular path. 
     
     
       8. The method of claim 5; including the step of changing the orientation of the stock after the step of moving a cutting tool along a path generally parallel to the labial surface of the bracket, and before the step of moving a cutting tool along a path about an axis generally perpendicular to the occlusal plane. 
     
     
       9. The method of claim 5, wherein said step of shaping stock includes the step of shaping round stock in a lathe.